<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			#a3{
				height: 400px;
				width: 400px;
				
				background-image: linear-gradient(red,blue,green,yellow);
				margin: 200px auto;
			}
			#a3:hover{
				/* transform: rotate(180deg); */
				transform: rotate3d(0.5,0.8,0.5,40deg);
			}
		</style>
	</head>
	<body>
		<div id="a3">
			
		</div>
	</body>
</html>